The present invention is directed generally to circuit monitoring devices, and more particularly, to an improved high impedance voltage indicator.
Various devices have been developed for indicating the voltage level on electrical conductors in high voltage power distribution systems.
One such early device was an electroscope wherein a pivoted vane was arranged to be repelled from a fixed vane on contact with an energized line. This device had to be positioned very precisely since the force of electrostatic repulsion of the vanes was relatively small and opposed by gravity. Another early device utilized an electromechanical meter movement in conjunction with a high resistance series resistor to ground. This device was cumbersome, and could not detect small charges and at high voltages required a high potential impedance return path to ground.
The present invention overcomes these drawbacks by providing a voltage indicator which incorporates a high impedance non-mechanical visual display device in the form of a liquid crystal display. This results in an indicator of increased sensitivity which is more compact and easier to manufacture, and which provides a large non-ambiguous indication of voltage level to the user.
Accordingly, it is a general object of the present invention to provide a new and improved voltage indicator.
It is a more specific object of the present invention to provide a voltage indicator which avoids the use of electromechanical indicator mechanisms and batteries.
It is a still more specific object of the invention to provide a voltage indicator which is more compact and less costly to manufacture.